苏氏圆腹Mang人工繁殖与育苗技术

苏氏圆腹Mang经4冬龄培育达性成熟，人工催产，雌雄1：1配组，多种激素混合使用，共催产亲鱼36组，产卵22组、2500万粒。孵出鱼苗500万尾，最高受精率80％，最高孵化率70％。提高育苗成活率是技术研究重点。     

太阳鱼人工杂交繁殖技术研究

利用人工催产、自然产卵受精技术,对30组蓝鳃太阳鱼(♂)和绿鳃太阳鱼(♀)亲鱼成功地进行人工杂交繁殖试验。在第2次注射催产剂36h后亲鱼开始产卵,4d后产卵结束,共产卵9组,产卵率30%,产卵4.95万粒,受精卵约4万粒,受精率约82.2%。经38~50 h孵化,出苗3.4万尾,孵化率85%。获3 cm苗种2.5万尾,成活率73.5%     

乌鳢规模化繁育技术

2000年6月催产50组成熟亲鱼，网箱静水孵化，共产卵89．5万粒，受精度90％，孵化率98％，培育成3－4cm的鱼种48．3万尾，总投入19480元，产出12．435万元，投入产出比为1：6．38。     

乌鳢人工繁殖试验初探

１９９６年５月２８日，选择１７组乌鳢亲鱼，在孵化槽、产卵池进行人工催产孵化。用轮叶黑藻、水荷叶作鱼巢，一次注射ＤＯＭ加ＬＲＨ－Ａ，催产率、受精率、孵化率分别为１００％、８２．９％、７１．７％。共出苗２０．８万尾。     

唇(鱼骨)人工繁殖和鱼苗培育初步研究

对唇(鱼骨)(Hemibarbus labeo)的亲鱼培育、人工繁殖、孵化和鱼苗培育等技术进行了初步研究.试验结果表明:唇(鱼骨)野生亲本在池塘条件下经人工驯养可达性成熟;在水温19.0～21.0 ℃时一次性注射LHR-A2、HCG和DOM混合催产剂,其效应时间18～21.5 h;2005～2006年采用人工催产、自然产卵及人工授精、流水孵化、豆浆法培育鱼苗等方法,共催产雌鱼44尾,平均催产率81.5%,共计产卵45.7万粒,平均受精率82.6%,孵化率77.4%,共孵出鱼苗24.5万尾.鱼苗经25～30 d豆浆法培育后可达3 cm以上,平均成活率为65.5%,共培育夏花15.1万尾.     

加州鲈人工繁殖技术

采用平均体重为0.5kg的加州鲈（Micropterus salmoides)亲鱼雌雄各221尾（221对），人工催产3d后开始产卵，经40d共产卵988批，889.2万粒，出苗711.4万尾，孵化率80%，经20-30d的培育共获2-5cm的幼鱼370万尾，居活率52%，结果表明：加州鲈具有极强的繁殖力；其卵母细胞具有分批成熟，分批产卵的习性；加州鲈亲鱼的产卵量与卵母细胞成熟度有关，与温度无关。     

花hua人工繁殖技术的研究

2000—2002年进行人工催产获得成功，利用养殖的子代作为亲本进行人工繁殖，共催产942组，产卵828万粒，受精率83．9％，出苗568万尾，孵化率81．8％，为花hua繁育探索了一条新途径。     

青鱼人工繁殖试验

用高效催产合剂人工催产青鱼5组，雌雄比1：1。总剂量为LRH－A285μg/kg RES15mg/kg。产卵率为80％，受精率为43％，孵化青鱼苗30万尾。     

使用LRH类似物及衍生物催产家鱼试验

在四川省农科院的协作下，我站于今年5月6日至7日用四川省农科院生产的LRH类似物催产鲢鱼1组，产卵70万粒，鳙鱼1组，产卵65万粒，受精率90％。用LRH类似物的衍生物催产草鱼3组，产卵300万粒，受精率80％，两种新催产剂均获成功，效果良好。     

泥鳅规模人工繁殖试验

2000年6月19日25日对泥鳅的繁殖季节、雌雄配比、注射方法、催产激素剂量、人工鱼巢的设置、苗种培育进行了研究，人工繁殖试验共催产亲鱼5批299组，产卵20万粒，出苗14万尾左右。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

The optimal dietary protein level of juvenile silver sillago Sillago sihama at three dietary lipid levels

A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p < .05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p < .05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p < .05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg.